CVE-2026-25536

HIGHPre-NVD 7.17.1—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 81% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.1Exploit: None knownExposed: 0

A fix is available — apply it.

MCP TypeScript SDK is the official TypeScript SDK for Model Context Protocol servers and clients. From version 1.10.0 to 1.25.3, cross-client response data leak when a single McpServer/Server and transport instance is reused across multiple client connections, most commonly in stateless StreamableHTTPServerTransport deployments. This issue has been patched in version 1.26.0.

CVSS v3
7.1
EG Score
7.1(medium)
EG Risk
32(Track)
EG Risk 32/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity71% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
18%
KEV
Not listed

Published

February 4, 2026

Last Modified

July 15, 2026

Advisory Details (7)

Auto-updated Jul 15, 2026
Patch available. Sources: github, redhat.
redhat Patch Available
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25536.json
redhat

2436937 – (CVE-2026-25536) CVE-2026-25536 @modelcontextprotocol/sdk: @modelcontextprotocol/sdk cross-client data leak

https://bugzilla.redhat.com/show_bug.cgi?id=2436937
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-25536
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:3960
github Patch Available

Sharing server/transport instances can leak cross-client response data · Advisory · modelcontextprotocol/typescript-sdk · GitHub

https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-345p-7cg4-v4c7
generic

How to use MCP client in a multi-user application? · Issue #243 · modelcontextprotocol/typescript-sdk · GitHub

https://github.com/modelcontextprotocol/typescript-sdk/issues/243
generic

Multiple clients to the same SSE connection? · Issue #204 · modelcontextprotocol/typescript-sdk · GitHub

https://github.com/modelcontextprotocol/typescript-sdk/issues/204

Vendor Advisories for CVE-2026-25536(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatansible-automation-platform-tech-preview/mcp-server-rhel9:17721962222026-03-06redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
@modelcontextprotocol/sdk—1.26.0—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 5× in last 7d / 40× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 148 total refreshes for this CVE.

  1. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-28 21:41 UTCEPSS rescore
  3. 2026-08-27 14:25 UTCEPSS rescore
  4. 2026-08-26 14:46 UTCEPSS rescore
  5. 2026-08-25 13:48 UTCEPSS rescore
  6. 2026-08-23 00:19 UTCEPSS rescore
  7. 2026-08-21 23:49 UTCEPSS rescore
  8. 2026-08-20 22:55 UTCEPSS rescore
  9. 2026-08-19 17:03 UTCEPSS rescore
  10. 2026-08-18 13:48 UTCEPSS rescore
  11. 2026-08-17 13:47 UTCEPSS rescore
  12. 2026-08-16 14:56 UTCEPSS rescore
  13. 2026-08-16 02:14 UTCEPSS rescore
  14. 2026-08-15 01:30 UTCEPSS rescore
  15. 2026-08-14 23:02 UTCVendor advisory
  16. 2026-08-14 11:10 UTCEG score recompute
  17. 2026-08-14 11:10 UTCVendor advisory
  18. 2026-08-13 22:00 UTCEPSS rescore
  19. 2026-08-13 03:29 UTCEG score recompute
  20. 2026-08-13 03:29 UTCVendor advisory
  21. 2026-08-12 13:50 UTCEPSS rescore
  22. 2026-08-11 13:42 UTCEPSS rescore
  23. 2026-08-11 00:00 UTCEPSS rescore
  24. 2026-08-10 03:42 UTCVendor advisory
  25. 2026-08-09 15:49 UTCEG score recompute
Show 75 more
  1. 2026-08-09 15:49 UTCVendor advisory
  2. 2026-08-09 13:46 UTCEPSS rescore
  3. 2026-08-08 16:37 UTCEPSS rescore
  4. 2026-08-07 22:45 UTCEG score recompute
  5. 2026-08-07 22:45 UTCVendor advisory
  6. 2026-08-06 13:46 UTCEPSS rescore
  7. 2026-08-06 04:21 UTCEG score recompute
  8. 2026-08-06 04:21 UTCVendor advisory
  9. 2026-08-05 19:17 UTCEPSS rescore
  10. 2026-08-04 15:10 UTCEPSS rescore
  11. 2026-08-03 10:36 UTCEPSS rescore
  12. 2026-08-02 21:24 UTCEG score recompute
  13. 2026-08-02 21:24 UTCVendor advisory
  14. 2026-08-02 02:26 UTCEPSS rescore
  15. 2026-08-01 04:16 UTCEPSS rescore
  16. 2026-07-30 22:51 UTCOSV refresh
  17. 2026-07-30 16:27 UTCEPSS rescore
  18. 2026-07-30 01:30 UTCEPSS rescore
  19. 2026-07-28 15:36 UTCEPSS rescore
  20. 2026-07-26 14:54 UTCEPSS rescore
  21. 2026-07-26 14:54 UTCEPSS rescore
  22. 2026-07-25 14:18 UTCEPSS rescore
  23. 2026-07-25 14:17 UTCEPSS rescore
  24. 2026-07-24 14:17 UTCEPSS rescore
  25. 2026-07-23 14:18 UTCEPSS rescore
  26. 2026-07-23 14:18 UTCEPSS rescore
  27. 2026-07-23 03:07 UTCEG score recompute
  28. 2026-07-22 14:08 UTCEPSS rescore
  29. 2026-07-20 17:08 UTCEPSS rescore
  30. 2026-07-19 14:31 UTCEPSS rescore
  31. 2026-07-19 14:31 UTCEPSS rescore
  32. 2026-07-19 02:29 UTCEPSS rescore
  33. 2026-07-19 02:28 UTCEPSS rescore
  34. 2026-07-18 10:04 UTCEPSS rescore
  35. 2026-07-18 10:04 UTCEPSS rescore
  36. 2026-07-16 17:03 UTCEPSS rescore
  37. 2026-07-16 17:03 UTCEPSS rescore
  38. 2026-07-15 16:57 UTCEPSS rescore
  39. 2026-07-15 16:57 UTCEPSS rescore
  40. 2026-07-15 02:00 UTCEPSS rescore
  41. 2026-07-15 02:00 UTCEPSS rescore
  42. 2026-07-13 22:30 UTCEPSS rescore
  43. 2026-07-13 08:07 UTCOSV refresh
  44. 2026-07-13 06:13 UTCEPSS rescore
  45. 2026-07-13 06:13 UTCEPSS rescore
  46. 2026-07-12 05:46 UTCEPSS rescore
  47. 2026-07-12 05:46 UTCEPSS rescore
  48. 2026-07-11 08:27 UTCEPSS rescore
  49. 2026-07-09 19:10 UTCEPSS rescore
  50. 2026-07-08 15:15 UTCEPSS rescore
  51. 2026-07-08 15:15 UTCEPSS rescore
  52. 2026-07-07 13:46 UTCEPSS rescore
  53. 2026-07-06 16:27 UTCEPSS rescore
  54. 2026-07-06 16:27 UTCEPSS rescore
  55. 2026-07-06 02:23 UTCEPSS rescore
  56. 2026-07-06 02:23 UTCEPSS rescore
  57. 2026-07-05 02:30 UTCEPSS rescore
  58. 2026-07-04 06:31 UTCEPSS rescore
  59. 2026-07-04 06:31 UTCEPSS rescore
  60. 2026-07-01 15:06 UTCEPSS rescore
  61. 2026-07-01 15:06 UTCEPSS rescore
  62. 2026-06-30 23:22 UTCEPSS rescore
  63. 2026-06-30 23:22 UTCEPSS rescore
  64. 2026-06-29 14:06 UTCEPSS rescore
  65. 2026-06-28 14:07 UTCEPSS rescore
  66. 2026-06-28 14:07 UTCEPSS rescore
  67. 2026-06-28 04:56 UTCEPSS rescore
  68. 2026-06-28 04:56 UTCEPSS rescore
  69. 2026-06-27 03:08 UTCEPSS rescore
  70. 2026-06-25 13:49 UTCEPSS rescore
  71. 2026-06-25 13:49 UTCEPSS rescore
  72. 2026-06-24 22:01 UTCOSV refresh
  73. 2026-06-24 14:05 UTCEPSS rescore
  74. 2026-06-24 14:05 UTCEPSS rescore
  75. 2026-06-23 21:33 UTCEPSS rescore

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-25536?
CVE-2026-25536 is a high vulnerability published on February 4, 2026. MCP TypeScript SDK is the official TypeScript SDK for Model Context Protocol servers and clients. From version 1.10.0 to 1.25.3, cross-client response data leak when a single McpServer/Server and transport instance is reused across multiple client connections, most commonly in stateless…
When was CVE-2026-25536 disclosed?
CVE-2026-25536 was first published in the National Vulnerability Database on February 4, 2026, with the most recent update on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-25536 actively exploited?
CVE-2026-25536 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 81.5% of all scored CVEs.
What is the CVSS score of CVE-2026-25536?
CVE-2026-25536 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2026-25536?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-25536, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-25536

Explore →

Is Your Infrastructure Affected by CVE-2026-25536?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs